Method for operating an internal combustion engine and device for carrying out the method

A device for operating an internal combustion engine comprising at least one control unit programmed to implement a method of operating an internal combustion engine having an exhaust gas section with at least one SCR catalytic converter whose NOx conversion efficiency is regulated with a reagent substance;

• the method including calculating a NOx current occurring downstream after the SCR catalytic convert;
• measuring a NOx current occurring downstream after the SCR catalytic converter with a NOx sensor, wherein the NOx sensor has a lateral sensitivity to the reagent substance;
• calculating a difference between the calculated NOx current and the measured NOx current;
• generating a reagent substance signal which establishes the dosage of the reagent substance, wherein the reagent substance signal is a function of the difference between the calculated NOx current and the measured NOx current;
• providing the established dosage of the reagent substance to the SCR catalytic converter;
• and performing a plausibility check wherein a correction signal, which influences the reagent substance signal, is generated upon deviation of a comparison of a reagent substance quantity metered in a predefined time period with a reagent quantity converted in the SCR catalytic converter and a NOx quantity.